Performance Review, Winter 1997

by
Tom Bruursema
NSF International

As the biological safety cabinet industry continues to grow, and international trade barriers are lowered, the field certifier industry must become global in their knowledge of standards and technology. This article is the first of several which will begin to provide a greater understanding and appreciation, of these global activities. Future articles will address more specific differences between the EN and NSF Standards, and other international standards.

The international community, as a means to facilitate free trade and economic prosperity, is making great strides towards developing uniform product standards for use throughout the world. This effort comes with many obstacles, including language barriers, differences in economic and technological development, conflicts with existing standards, independent views and opinions, political constraints, coordination of worldwide input and review, and ultimately, global acceptance.

In an attempt to further this vision, the European community has elected to develop a unified set of standards. The goal is to have standards which are accepted, and adopted, by all the European countries. These European standards are commonly referred to as the European Norm (EN). The body providing the leadership for the development of such uniform standards is referred to as the European Committee for Standardization (CEN).

Member countries represented on the CEN include Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom.

For the past several years the CEN has been developing a European Norm for biological safety cabinets, as coordinated by the Technical Committee on Biotechnology (CEN/TC 233). The draft standard, titled "Performance Criteria for Microbiological Safety Cabinets" (prEN 12469), specifies basic requirements for cabinets with respect to safety and hygiene, including minimum performance criteria for protection of the operator, the environment, the product and cross contamination. The standard currently includes many similarities to NSF Standard 49, as well as some differences.

The basic description of the cabinets covered by each of the respective standards is basically the same, directed at those intended to provide containment of aerosols with biologically active substances, and excluding radioactive, toxic, and corrosive substances. One immediate difference, however, is that Standard 49 is applicable to Class II cabinets only, whereas the EN Standard applies to Class I, II, and III.

A further, obvious difference can be found in the definition of cabinets. Standard 49 divides Class II into four types (A, B1, B2, and B3). Conversely, the EN Standard recognizes only one, falling somewhere between a type A and B. According to Standard 49, type A cabinets are required to have a minimum inflow velocity of 0.38m/s (75 fpm), and type B a minimum of 0.5m/s (100 fpm). The EN Standard has one minimum requirement of 0.4 m/s (80 fpm). Further, Standard 49 does not establish a minimum downflow velocity, unlike the EN Standard which requires a minimum of 0.4 m/s (80 fpm).

Requirements exist in both standards for lighting, noise, vibration, stability, materials, electrical, safety, temperature, leakage, and demonstration of microorganism containment. There are minor differences in the testing and acceptance criteria for those various requirements.

Further similarities can be found in the additional information provided in the annexes, including detailed test procedures, recommended field testing and procedures for decontamination.

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